Backend-Api/ServiceHost/Hubs/FaceEmbeddingHub.cs

using Microsoft.AspNetCore.SignalR;

namespace ServiceHost.Hubs
{
    public class FaceEmbeddingHub : Hub
    {
        public async Task JoinWorkshopGroup(long workshopId)
        {
            await Groups.AddToGroupAsync(Context.ConnectionId, GetGroupName(workshopId));
        }

        public async Task LeaveWorkshopGroup(long workshopId)
        {
            await Groups.RemoveFromGroupAsync(Context.ConnectionId, GetGroupName(workshopId));
        }

        public static string GetGroupName(long workshopId)
        {
            return $"group-faceembedding-{workshopId}";
        }
    }
}